4.5 Finish mode

Finish mode has two functions. One is to help system administrators
install libtool libraries so that they can be located and linked into
user programs. To invoke this functionality, pass the name of a library
directory as mode-arg. Running this command may require superuser
privileges, and the --dry-run option may be useful.

The second is to facilitate transferring libtool libraries to a native
compilation environment after they were built in a cross-compilation
environment. Cross-compilation environments may rely on recent libtool
features, and running libtool in finish mode will make it easier to
work with older versions of libtool. This task is performed whenever
the mode-arg is a .la file.